Abstracts

Rationale: Depression is a highly prevalent, but undertreated comorbidity in people with epilepsy (PWE). The Neurological Disorders Depression Inventory in Epilepsy (NDDI-E) is an epilepsy-specific, self-report depression screening questionnaire that has been validated against the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID 1-research version). Scores of ≥15 indicate a likely major depressive episode. Other self-report instruments, such the BDI-II, can also be used to measure the severity of depressive symptoms in a variety of medical conditions. Advantages of the NDDI-E include: brevity (6 items) and its focus of identifying depressive symptoms more common in PWE. Besides screening for depressive symptoms, it is also important that clinicians are able to quickly measure outcomes of AED intervention. This analysis examined the utility of the NDDI-E in measuring change in depressive symptoms following AED therapy. Methods: The NDDI-E and BDI-II were used in 2 studies assessing the effects of lamotrigine as adjunctive treatment in PWE. Study 1 (LAM40117) was a 19 week open-label trial in 158 patients who had at least low to moderate levels of depression at baseline. Study 2 (LAM40124) was a 20 week blinded, active-control (levetiracetam) trial in 268 patients with partial seizures. In each study, both the NDDI-E and BDI-II were administered at baseline and endpoint (end of adjunctive treatment). Mood changes were measured by self-report scores on the BDI-II and NDDI-E. Observed scores are reported. Results: In Study 1, patients had baseline NDDI-E and BDI-II scores of 13.5 and 17.4 respectively. At endpoint, mean change from baseline was -2.0 (p<0.0001) for the NDDI-E and -7.3 (p<0.0001) for the BDI-II. Spearman correlation was 0.59 (p<0.0001). In Study 2, patients had baseline NDDI-E and BDI-II scores of 11.9 and 12.5 respectively. At endpoint, mean change from baseline was -0.72 (p=0.0018) for the NDDI-E and -1.3 (p=0.0179) for the BDI-II. Spearman correlation was 0.54 (p<0.0001). Conclusions: The significant correlation of change scores of the NDDI-E and BDI-II across two different studies provides evidence for utilizing the NDDI-E to measure change in depressive symptoms in PWE after adjunctive AED therapy.